I am getting a 400 error on all my pages when I moved my django app from one hosting service to another, the hosting service I moved to is Scalingo.
My settings.py file:
DEBUG = os.getenv("DEBUG") == "True"
ALLOWED_HOSTS = [x.strip() for x in os.getenv("ALLOWED_HOSTS").split(",")]
My env variables
ALLOWED_HOSTS="my-app.osc-fr.scalingo.fr,.localhost,127.0.0.1,[::1]"
DEBUG="False"
I contacted customer support who have advised me that it must be a configuration issue with my app.
All existing answers here I have found have advised to make sure the ALLOWED_HOSTS variable is correct, and I have already checked that it includes the required addresses according to the hosting platform's django-specific docs.
In the end I debugged the problem by doing a print(ALLOWED_HOSTS) in the settings.py file and inspecting the build logs.
Turns out the environment variables on this platform were being loaded with the quotation marks included, resulting in ['"my-app.osc-fr.scalingo.fr','.localhost','127.0.0.1','[::1]"'].
I edited the environment variables to remove the quotation marks and it works!
Not sure why the quotation marks were taken into account though, given that I can have them in on other hosting platforms and locally and they get ignored. If anyone knows I'd be interested to find out!